Fig. 2
[18F]FDG- and [18F]DPA-714-μPET imaging after closed head weight-drop TBI in mice. a Representative transverse images of [18F]FDG-μPET, 2 days after TBI show an area of no [18F]FDG uptake within the focal cortical lesion of a TBI mouse (white arrow head), in contrast to a uniform [18F]FDG uptake in sham-operated and mTBI mice. b–d Representative transverse images of 18F]DPA-714-μPET on the left and semi-quantitative analyses of these data on the right. Arrowheads in the μPET images in panels. c, d The visible overlap of [18F]DPA-714 uptake on days 7 and 16 with the reduction of the [18F]FDG uptake on day 2 (a). b [18F]DPA-714-μPET on day 1 after TBI shows no significant difference in [18F]DPA-714 uptake between sham (n = 5), mTBI (n = 12), and TBI (n = 8) mice. c [18F]DPA-714-μPET on day 7 after TBI. Compared to the sham animals (0.7 ± 0.2, mean ± SD, n = 6), the lesion-to-cerebellum (L/C) ratio was not significantly increased in mTBI mice (0.8 ± 0.3, n = 12), but it was significantly increased in TBI mice (1.9 ± 0.5, n = 10) as compared to both sham and mTBI mice. d [18F]DPA-714-μPET on day 16 after TBI. The L/C ratio of three mTBI and three TBI mice. e Time-course of the L/C ratio in the three groups (data identical to bar graphs in b–d. The L/C ratio of TBI mice significantly increased from 0.61 on day 1 to 1.85 on day 7 as compared to both sham-operated and mTBI mice and the decreased to 1.38 on day 16. In mTBI mice the L/C ratio was not statistically different from that in sham group even if it tended to increase from 0.67 on day 1 to 0.82 on day 16. f Linear regression analysis between [18F]FDG uptake on days 2–5 and [18F]DPA-714 accumulation on day 7 show a highly significant correlation between reduced brain metabolic activity and [18F]DPA-714 uptake.***p < 0.001 in c and e